function show(title, url, w, h) {
    if (title == null || title == '') title = false;
    if (url == null || url == '') url = "404.html";
    if (w == null || w == '' || $(window).width() < w) w = ($(window).width() * 0.9);
    if (h == null || h == '' || $(window).height() < h) h = ($(window).height() - 50);
    var index = layer.open({
        type: 2,
        area: [w + 'px', h + 'px'],
        fix: false, //不固定
        maxmin: false,
        shadeClose: true,
        shade: 0.4,
        title: title,
        content: url
    });
}